Lens system, image capturing unit and electronic device

ABSTRACT

A lens system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element. The first lens element with negative refractive power has a concave image-side surface in a paraxial region. The second lens element with refractive power has a convex object-side surface in a paraxial region. The third lens element has positive refractive power. The fourth lens element with positive refractive power has an object-side and an image-side surfaces being aspheric. The fifth lens element with negative refractive power has an aspheric concave object-side surface and an aspheric convex image-side surface in a paraxial region. The sixth lens element with refractive power has an image-side surface being concave in a paraxial region with a convex shape in an off-axis region.

RELATED APPLICATIONS

This application is a continuation patent application of U.S. Pat. No.9,606,327 B2, filed Jun. 15, 2015, which claims priority to TaiwanApplication 104106261, filed Feb. 26, 2015, which is incorporated byreference herein in its entirety.

BACKGROUND

Technical Field

The present disclosure relates to a lens system, an image capturing unitand an electronic device, more particularly to a lens system and animage capturing unit applicable to an electronic device.

Description of Related Art

In recent years, with the popularity of electronic devices having camerafunctionalities, the demand of miniaturized optical systems has beenincreasing. The sensor of a conventional optical system is typically aCCD (Charge-Coupled Device) or a CMOS (ComplementaryMetal-Oxide-Semiconductor) sensor. As the advanced semiconductormanufacturing technologies have allowed the pixel size of sensors to bereduced and compact optical systems have gradually evolved toward thefield of higher megapixels, there is an increasing demand for compactoptical systems featuring better image quality.

A conventional optical system employed in a portable electronic productmainly adopts a five-element lens structure. Due to the popularity ofmobile terminals with high-end specifications, such as smart phones,tablet personal computers and wearable apparatuses, the requirements forhigh resolution and image quality of present compact optical systemsincrease significantly. However, the conventional optical systems cannotsatisfy these requirements of the compact optical systems.

Other conventional compact optical systems with six-element lensstructure having a large aperture are developed to enhance resolutionand image quality. However, the optical systems are unfavorable forsatisfying the requirements of large field of view and compact sizesimultaneously so that it is unfavorable for equipping the opticalsystems on a compact electronic device.

SUMMARY

According to one aspect of the present disclosure, a lens systemincludes, in order from an object side to an image side, a first lenselement, a second lens element, a third lens element, a fourth lenselement, a fifth lens element, and a sixth lens element. The first lenselement with negative refractive power has an image-side surface beingconcave in a paraxial region thereof. The second lens element withrefractive power has an object-side surface being convex in a paraxialregion thereof. The third lens element has positive refractive power.The fourth lens element has positive refractive power, wherein anobject-side surface and an image-side surface of the fourth lens elementare both aspheric. The fifth lens element with negative refractive powerhas an object-side surface being concave in a paraxial region thereofand an image-side surface being convex in a paraxial region thereof,wherein the object-side surface and the image-side surface of the fifthlens element are both aspheric. The sixth lens element with refractivepower has an image-side surface being concave in a paraxial regionthereof, wherein the image-side surface of the sixth lens element has atleast one convex shape in an off-axis region thereof, and an object-sidesurface and the image-side surface of the sixth lens element are bothaspheric. The lens system has a total of six lens elements withrefractive power. There is an air gap in a paraxial region between everytwo of the first lens element, the second lens element, the third lenselement, the fourth lens element, the fifth lens element and the sixthlens element that are adjacent to each other. At least three of thefirst lens element, the second lens element, the third lens element, thefourth lens element, the fifth lens element and the sixth lens elementare made of plastic material. When a focal length of the lens system isf, a focal length of the first lens element is f1, a focal length of thesecond lens element is f2, a focal length of the third lens element isf3, a focal length of the fourth lens element is f4, the followingconditions are satisfied:|f1/f2|<1.20; and0.80<(f/f3)+(f/f4).

According to another aspect of the present disclosure, an imagecapturing unit includes the aforementioned lens system and an imagesensor, wherein the image sensor is disposed on the image side of thelens system.

According to still another aspect of the present disclosure, anelectronic device includes a plurality of image capturing units. Each ofthe image capturing units comprises a lens system and an image sensor.The image sensor is disposed on an image side of the lens system. Thelens systems are single focus lens systems. The lens systems havedifferent fields of view. At least one of the lens systems is the lenssystem according to the aforementioned lens system.

According to yet another aspect of the present disclosure, a lens systemincludes, in order from an object side to an image side, a first lenselement, a second lens element, a third lens element, a fourth lenselement, a fifth lens element, and a sixth lens element. The first lenselement with negative refractive power has an image-side surface beingconcave in a paraxial region thereof. The second lens element hasrefractive power. The third lens element has positive refractive power.The fourth lens element has positive refractive power. The fifth lenselement with negative refractive power has an object-side surface beingconcave in a paraxial region thereof and an image-side surface beingconvex in a paraxial region thereof, wherein the object-side surface andthe image-side surface of the fifth lens element are both aspheric. Thesixth lens element with refractive power has an image-side surface beingconcave in a paraxial region thereof, wherein the image-side surface ofthe sixth lens element has at least one convex shape in an off-axisregion thereof, and an object-side surface and the image-side surface ofthe sixth lens element are both aspheric. The lens system has a total ofsix lens elements with refractive power. There is an air gap in aparaxial region between every two of the first lens element, the secondlens element, the third lens element, the fourth lens element, the fifthlens element and the sixth lens element that are adjacent to each other.At least three of the first lens element, the second lens element, thethird lens element, the fourth lens element, the fifth lens element andthe sixth lens element are made of plastic material. When a focal lengthof the lens system is f, a focal length of the first lens element is f1,a focal length of the second lens element is f2, a focal length of thethird lens element is f3, a focal length of the fourth lens element isf4, and the following conditions are satisfied:|f1/f2|<1.20;1.60<(f/f3)+(f/f4); and0<f3/f4<3.0.

According to yet another aspect of the present disclosure, a lens systemincludes, in order from an object side to an image side, a first lenselement, a second lens element, a third lens element, a fourth lenselement, a fifth lens element, and a sixth lens element. The first lenselement has negative refractive power. The second lens element hasrefractive power. The third lens element has refractive power. Thefourth lens element has refractive power. The fifth lens element hasrefractive power, wherein an object-side surface and an image-sidesurface of the fifth lens element are both aspheric. The sixth lenselement has refractive power, wherein an image-side surface of the sixthlens element has at least one inflection point in an off-axis regionthereof, and an object-side surface and the image-side surface of thesixth lens element are both aspheric. The lens system has a total of sixlens elements with refractive power. When an axial distance between anobject-side surface of the first lens element and an image surface isTL, half of a maximal field of view of the lens system is HFOV, amaximum effective radius of the object-side surface of the first lenselement is SD11, a maximum effective radius of the image-side surface ofthe sixth lens element is SD62, a maximum image height of the lenssystem is ImgH, the following conditions are satisfied:TL/sin(HFOV*1.6)<7.0 mm;1.30<tan(HFOV);|SD11/SD62|<2.40; andTL/ImgH<2.50.

According to yet another aspect of the present disclosure, an electronicdevice comprises a first image capturing unit, a second image capturingunit and a third image capturing unit. The first image capturing unitcomprises a first lens system and an image sensor. The image sensor isdisposed on an image side of the first lens system. The first lenssystem comprises an object-side lens element being the closest lenselement to an imaged object among all lens elements of the first lenssystem with refractive power. The second image capturing unit comprisesa second lens system. The third image capturing unit comprises a thirdlens system. The first image capturing unit, the second image capturingunit, and the third image capturing unit have different fields of viewfrom one another. The first lens system, the second lens system and thethird lens system are all single focus lens systems. When half of amaximal field of view of the first lens system is HFOV, an axialdistance between an object-side surface of the object-side lens elementand an image surface is TL, a maximum image height of the first lenssystem is ImgH, and the following conditions are satisfied:TL/sin(HFOV*1.6)<10.0 mm;0.70<tan(HFOV); andTL/ImgH<3.0.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be more fully understood by reading the followingdetailed description of the embodiments, with reference made to theaccompanying drawings as follows:

FIG. 1 is a schematic view of an image capturing unit according to the1st embodiment of the present disclosure;

FIG. 2 shows spherical aberration curves, astigmatic field curves and adistortion curve of the image capturing unit according to the 1stembodiment;

FIG. 3 is a schematic view of an image capturing unit according to the2nd embodiment of the present disclosure;

FIG. 4 shows spherical aberration curves, astigmatic field curves and adistortion curve of the image capturing unit according to the 2ndembodiment;

FIG. 5 is a schematic view of an image capturing unit according to the3rd embodiment of the present disclosure;

FIG. 6 shows spherical aberration curves, astigmatic field curves and adistortion curve of the image capturing unit according to the 3rdembodiment;

FIG. 7 is a schematic view of an image capturing unit according to the4th embodiment of the present disclosure;

FIG. 8 shows spherical aberration curves, astigmatic field curves and adistortion curve of the image capturing unit according to the 4thembodiment;

FIG. 9 is a schematic view of an image capturing unit according to the5th embodiment of the present disclosure;

FIG. 10 shows spherical aberration curves, astigmatic field curves and adistortion curve of the image capturing unit according to the 5thembodiment;

FIG. 11 is a schematic view of an image capturing unit according to the6th embodiment of the present disclosure;

FIG. 12 shows spherical aberration curves, astigmatic field curves and adistortion curve of the image capturing unit according to the 6thembodiment;

FIG. 13 is a schematic view of an image capturing unit according to the7th embodiment of the present disclosure;

FIG. 14 shows spherical aberration curves, astigmatic field curves and adistortion curve of the image capturing unit according to the 7thembodiment;

FIG. 15 is a schematic view of a maximum effective radius of anobject-side surface of a first lens element and a maximum effectiveradius of an image-side surface of a sixth lens element in FIG. 1;

FIG. 16 shows an electronic device according to one embodiment;

FIG. 17 is shows a side view of the electronic device in FIG. 16;

FIG. 18 shows an arrangement of the image capturing units according toone embodiment;

FIG. 19 shows an arrangement of the image capturing units according toanother embodiment; and

FIG. 20 shows an arrangement of the image capturing units according tostill another embodiment.

DETAILED DESCRIPTION

A lens system includes, in order from an object side to an image side, afirst lens element, a second lens element, a third lens element, afourth lens element, a fifth lens element and a sixth lens element. Thelens system can have a total of six lens elements with refractive power.

According to the lens system of the present disclosure, in someembodiments, there is an air gap in a paraxial region arranged betweenevery two of the first lens element, the second lens element, the thirdlens element, the fourth lens element, the fifth lens element, and thesixth lens element that are adjacent to each other, that is, each of thefirst through sixth lens elements of the lens system can be a single andnon-cemented lens element. Moreover, the manufacturing process of thecemented lenses is more complex than the non-cemented lenses. Inparticular, an image-side surface of one lens element and an object-sidesurface of the following lens element need to have accurate curvature toensure these two lens elements will be highly cemented. However, duringthe cementing process, those two lens elements might not be highlycemented due to displacement and it is thereby not favorable for theimage quality of the lens system. Therefore, there is an air gap in aparaxial region between every two of the first lens element, the secondlens element, the third lens element, the fourth lens element, the fifthlens element and the sixth lens element that are adjacent to each otherin the present disclosure for solving the problem generated by thecemented lens elements. Furthermore, in some embodiments, the first lenselement, the second lens element, the third lens element, the fourthlens element, the fifth lens element and the sixth lens element are allstationary relative to each other in a paraxial region thereof, so thatit is favorable for the lens system being a single focus lens system.

The first lens element can have negative refractive power. The firstlens element can have an image-side surface being concave in a paraxialregion thereof. Therefore, it is favorable for enlarging a field of viewof the lens system so as to capture a large image.

The second lens element with refractive power can have an object-sidesurface being convex in a paraxial region thereof. Therefore, it isfavorable for correcting the aberration from the first lens element soas to improve the image quality. Furthermore, it is favorable forreducing a total track length of the lens system.

The third lens element can have positive refractive power. The thirdlens element can have an image-side surface being convex in a paraxialregion thereof. Therefore, the first lens element and the third lenselement are favorable for balancing the arrangement of the refractivepower of the lens system so as to reduce the sensitivity of the lenssystem.

The fourth lens element can have positive refractive power. The fourthlens element can have an image-side surface being convex in a paraxialregion thereof. Therefore, it is favorable for correcting the Petzval'ssum of the lens system so as to improve the flatness of the imagesurface and reduce the astigmatism of lens system.

The fifth lens element can have negative refractive power. The fifthlens element can have an object-side surface being concave in a paraxialregion thereof and an image-side surface being convex in a paraxialregion thereof. The image-side surface of the fifth lens element canhave at least one concave shape in an off-axis region thereof.Therefore, it is favorable for correcting the spherical aberration ofthe lens system and the aberration of the off-axis region.

The sixth lens element can have positive refractive power. The sixthlens element can have an image-side surface being concave in a paraxialregion thereof. The image-side surface of the sixth lens element canhave at least one convex shape in an off-axis region thereof. Theimage-side surface of the sixth lens element can have at least oneinflection point in an off-axis region thereof. Therefore, it isfavorable for the principal point of the lens system being furtherpositioned away from the image side of the lens system so as to reducethe total track length of the lens system. Furthermore, it is favorablefor improving the image-sensing efficiency of the image sensor andfurther correcting the aberration of the off-axis region by effectivelyreducing the incident angle of the light projecting onto the imagesensor.

When a focal length of the first lens element is f1, a focal length ofthe second lens element is f2, the following condition is satisfied:|f1/f2|<1.20. Therefore, it is favorable for preventing the refractivepower of the second lens element from becoming too large. Furthermore,it is favorable for reducing the incident angle of the light so as toavoid excessive aberration.

When a focal length of the lens system is f, a focal length of the thirdlens element is f3, a focal length of the fourth lens element is f4, thefollowing condition is satisfied: 0.80<(f/f3)+(f/f4). Therefore, it isfavorable for assembling the lens elements with stronger refractivepower at proper positions so as to prevent the manufacturing toleranceof the lens elements from influencing the manufacturing yield rate.Preferably, the following condition is satisfied: 1.60<(f/f3)+(f/f4).More preferably, the following condition is satisfied:1.20<(f/f3)+(f/f4)<2.50.

When the focal length of the third lens element is f3, the focal lengthof the fourth lens element is f4, the following condition is satisfied:0<f3/f4<3.0. Therefore, the refractive powers of the third lens elementand the fourth lens element are properly distributed so that it isfavorable for correcting the aberration of the lens system and reducingthe sensitivity of the lens system.

When an axial distance between an object-side surface of the first lenselement and an image surface is TL, half of a maximal field of view ofthe lens system is HFOV, the following condition is satisfied:TL/sin(HFOV*1.6)<10 mm. Therefore, it is favorable for keeping the lenssystem compact and providing the lens system with sufficient field ofview. Preferably, the following condition is satisfied:TL/sin(HFOV*1.6)<7.0 mm.

When half of the maximal field of view of the lens system is HFOV, thefollowing condition is satisfied: 1.30<tan(HFOV). Therefore, it isfavorable for providing the lens system with a sufficient field of viewas the lens system needs to be so as to avoid image distortion.Preferably, the following condition is satisfied: 0.70<tan(HFOV).

When a maximum effective radius of the object-side surface of the firstlens element is SD11, a maximum effective radius of the image-sidesurface of the sixth lens element is SD62, the following condition issatisfied: |SD11/SD62|<2.40. Therefore, it is favorable for reducing thedifference between a diameter of the first lens element and a diameterof the sixth lens element so that it is favorable for convenientlyassembling the lens elements with a stable yield rate. Preferably, thefollowing condition is satisfied: |SD11/SD62|<1.25. As seen in FIG. 15,which is a schematic view of a maximum effective radius of anobject-side surface of a first lens element and a maximum effectiveradius of an image-side surface of a sixth lens element in FIG. 1.

When the axial distance between the object-side surface of the firstlens element and the image surface is TL, a maximum image height of thelens system (half of a diagonal length of an effective photosensitivearea of an image sensor) is ImgH, the following condition is satisfied:TL/ImgH<3.0. Therefore, it is favorable for keeping the lens systemcompact so as to be equipped in a compact electronic device. Preferably,the following condition is satisfied: TL/ImgH<2.50.

When a maximum effective radius of an object-side surface of anobject-side lens element is SDfs, a maximum effective radius of animage-side surface of an image-side lens element is SDls, the followingcondition can be satisfied: |SDfs/SDls|<1.25. Therefore, it is favorablefor reducing the difference between a diameter of the object-side lenselement and a diameter of the image-side lens element so that it isfavorable for conveniently assembling the lens elements with a stableyield rate. According to the present disclosure, the object-side lenselement is the closest lens element to an imaged object among all lenselements of the lens system with refractive power, and the image-sidelens element is the closest lens element to the image surface among alllens elements of the lens system with refractive power. For example,when the lens system includes a total of six lens elements withrefractive power which are, in order from the object side to the imageside, the first lens element, the second lens element, the third lenselement, the fourth lens element, the fifth lens element and the sixthlens element, the aforementioned object-side lens element is the firstlens element, and the aforementioned image-side lens element is thesixth lens element. Therefore, the maximum effective radius of theobject-side surface of the first lens element is SDfs, and the maximumeffective radius of the image-side surface of the sixth lens element isSDls.

According to the present disclosure, the lens system further includes astop which can be located between the first lens element and the secondlens element. When an axial distance between the stop and the image-sidesurface of the sixth lens element is SD, an axial distance between theobject-side surface of the first lens element and the image-side surfaceof the sixth lens element is TD, the following condition can besatisfied: 0.65<SD/TD<0.90. Therefore, it is favorable for obtaining abalance between the telecentric and the wide-angle characteristics.

When an axial distance between the first lens element and the secondlens element is T12, an axial distance between the fourth lens elementand the fifth lens element is T45, the following condition can besatisfied: 2.0<T12/T45. Therefore, the axial distances between every twoadjacent lens elements are properly distributed so that it is favorablefor assembling the lens elements so as to improve the manufacturingyield rate.

When the focal length of the lens system is f, a curvature radius of animage-side surface of a lens element being the closest one to the imagesurface among all lens elements with refractive power is RL, thefollowing condition can be satisfied: 0.4<f/RL<3.0. Therefore, it isfavorable for reducing a back focal length of the lens system so as tostay in a compact size thereof. In some embodiments, when the lenssystem includes a total of six lens elements with refractive power whichare, in order from the object side to the image side, the first lenselement, the second lens element, the third lens element, the fourthlens element, the fifth lens element and the sixth lens element withrefractive power, the aforementioned lens element being the closest oneto the image surface is the sixth lens element, and the curvature radiusof the image-side surface of the sixth lens element is RL.

When an Abbe number of the second lens element is V2, an Abbe number ofthe fifth lens element is V5, the following condition can be satisfied:V2+V5<60. Therefore, it is favorable for correcting the chromaticaberration of the lens system.

When the focal length of the lens system is f, a curvature radius of theobject-side surface of the second lens element is R3, the followingcondition can be satisfied: 0.25<f/R3. Therefore, it is favorable foravoiding overloading the refractive power on the second lens element soas to prevent the second lens element from being overly curved, therebyreducing molding problems.

When a maximum refractive index among the first lens element, the secondlens element, the third lens element, the fourth lens element, the fifthlens element and the sixth lens element is Nmax, the following conditioncan be satisfied: 1.60<Nmax<1.70. Therefore, it is favorable forproperly distributing the refractive power of the lens system whilechoosing proper material for each lens element.

When the axial distance between the object-side surface of the firstlens element and the image surface is TL, the following condition can besatisfied: TL<5.0 mm. Therefore, it is favorable for reducing the totaltrack length of the lens system so as to keep in a compact size thereof.

When the focal length of the lens system is f, an entrance pupildiameter of the lens system is EPD, the following condition can besatisfied: f/EPD<2.65. Therefore, it is favorable for obtaining a largeaperture for receiving sufficient incoming light, thereby increasing theimage quality in a low light condition.

According to the present disclosure, an aperture stop can be configuredas a front stop or a middle stop. A front stop disposed between animaged object and the first lens element can provide a longer distancebetween an exit pupil of the lens system and the image surface toproduce a telecentric effect, and thereby improves the image-sensingefficiency of an image sensor (for example, CCD or CMOS). A middle stopdisposed between the first lens element and the image surface isfavorable for enlarging the view angle of the lens system and therebyprovides a wider field of view for the same.

According to the present disclosure, the lens elements thereof can bemade of glass or plastic material. When the lens elements are made ofglass material, the distribution of the refractive power of the lenssystem may be more flexible to design. When the lens elements are madeof plastic material, the manufacturing cost can be effectively reduced.According to the present disclosure, at least three of the first lenselement, the second lens element, the third lens element, the fourthlens element, the fifth lens element and the sixth lens element are madeof plastic material. Furthermore, surfaces of each lens element can bearranged to be aspheric, since the aspheric surface of the lens elementis easy to form a shape other than spherical surface so as to have morecontrollable variables for eliminating the aberration thereof, and tofurther decrease the required number of the lens elements. Therefore,the total track length of the lens system can also be reduced.

According to the present disclosure, each of an object-side surface andan image-side surface has a paraxial region and an off-axis region. Theparaxial region refers to the region of the surface where light raystravel close to the optical axis, and the off-axis region refers to theregion of the surface away from the paraxial region. Particularly, whenthe lens element has a convex surface, it indicates that the surface isconvex in the paraxial region thereof; when the lens element has aconcave surface, it indicates that the surface is concave in theparaxial region thereof. Moreover, when a region of refractive power orfocus of a lens element is not defined, it indicates that the region ofrefractive power or focus of the lens element is in the paraxial regionthereof.

According to the present disclosure, an image surface of the lenssystem, based on the corresponding image sensor, can be flat or curved,especially a curved surface being concave facing towards the object sideof the lens system.

According to the present disclosure, the lens system can include atleast one stop, such as an aperture stop, a glare stop or a field stop.Said glare stop or said field stop is set for eliminating the straylight and thereby improving the image quality thereof.

According to the present disclosure, an image capturing unit isprovided. The image capturing unit includes the lens system according tothe aforementioned lens system of the present disclosure, and an imagesensor, wherein the image sensor is disposed on the image side of theaforementioned lens system, that is, the image sensor can be disposed onor near an image surface of the aforementioned lens system. In someembodiments, the image capturing unit can further include a barrelmember, a holding member or a combination thereof.

In FIG. 16 and FIG. 17, an image capturing device may be installed in,but not limited to, an electronic device, including a smart phone (FIG.16 and FIG. 17), a tablet personal computer or a wearable device. Theelectronic devices shown in the figures are only exemplary for showingthe image capturing device of the present disclosure installed in anelectronic device and are not limited thereto. In detail, according tothe present disclosure, the electronic device at least includes a firstimage capturing unit 10 a, a second image capturing unit 10 b and athird image capturing unit 10 c.

The first image capturing unit 10 a includes a first lens system and afirst image sensor. The second image capturing unit 10 b includes asecond lens system and a second image sensor. The third image capturingunit 10 c includes a third lens system and a third image sensor. Thefirst lens system 10 a, the second lens system 10 b and the third lenssystem 10 c are all single focus lens systems. The first lens system 10a, the second lens system 10 b and the third lens system 10 c havedifferent fields of view from one another. Among the first lens system10 a, the second lens system 10 b and the third lens system 10 c, thefirst lens system 10 a is the lens system according to the presentdisclosure. Therefore, the electronic device is for capturing the imagesby different image capturing units (For example, the electronic devicecaptures the images by an image capturing unit having a smaller field ofview and another having a larger field of view). Moreover, theelectronic device produces a composite image by combining the raw imagescaptured by the first image capturing unit 10 a, the second imagecapturing unit 10 b and the third image capturing unit 10 c withpost-processing techniques (such as digital zoom, depth of focus or 3Dimaging). Compared with a traditional electronic device including acomplex electro-mechanical part for zoom, the electronic device of thepresent disclosure is more favorable for keeping in a compact sizethereof.

According to the present disclosure, the number of the image capturingunits of the electronic device is not limited thereto. For example, theelectronic device can include more than three image capturing unitswhich utilize the lens systems according to the present disclosure.Furthermore, the first lens system 10 a, the second lens system 10 b andthe third lens system 10 c can be disposed in a vertical (FIG. 18),horizontal (FIG. 19) or triangular (FIG. 20) arrangement. According tothe present disclosure, the arrangement and the positions of the firstlens system 10 a, the second lens system 10 b and the third lens system10 c can be adjusted. In some embodiments, the electronic device canfurther include, but not limited to, a display unit, a control unit, astorage unit, a random access memory unit (RAM), a read only memory unit(ROM) or a combination thereof.

According to the present disclosure, the lens system can be optionallyapplied to moving focus optical systems. Furthermore, the lens system isfeatured with good capability in aberration corrections resulting highimage quality, and can be applied to 3D (three-dimensional) imagecapturing applications, in products such as digital cameras, mobiledevices, digital tablets, wearable devices, smart televisions, networksurveillance devices, motion sensing input devices, dashboard cameras,vehicle backup cameras and other electronic imaging devices. Accordingto the above description of the present disclosure, the followingspecific embodiments are provided for further explanation.

1st Embodiment

FIG. 1 is a schematic view of an image capturing unit according to the1st embodiment of the present disclosure. FIG. 2 shows, in order fromleft to right, spherical aberration curves, astigmatic field curves anda distortion curve of the image capturing unit according to the 1stembodiment. In FIG. 1, the image capturing unit includes the lens system(its reference numeral is omitted) of the present disclosure and animage sensor 190. The lens system includes, in order from an object sideto an image side, a first lens element 110, an aperture stop 100, asecond lens element 120, a third lens element 130, a fourth lens element140, a fifth lens element 150, a sixth lens element 160, an IR-cutfilter 170 and an image surface 180, wherein the lens system has a totalof six non-cemented lens elements (110-160) with refractive power. Thereis an air gap in a paraxial region between every two of the first lenselement 110, the second lens element 120, the third lens element 130,the fourth lens element 140, the fifth lens element 150 and the sixthlens element 160 that are adjacent to each other. In this embodiment,the first lens element 110 is an object-side lens element being theclosest lens element to an imaged object among all lens elements withrefractive power, and the sixth lens element 160 is an image-side lenselement being the closest lens element to the image surface 180 amongall lens elements with refractive power.

The first lens element 110 with negative refractive power has anobject-side surface 111 being concave in a paraxial region thereof andan image-side surface 112 being concave in a paraxial region thereof.The first lens element 110 is made of plastic material and has theobject-side surface 111 and the image-side surface 112 being bothaspheric.

The second lens element 120 with positive refractive power has anobject-side surface 121 being convex in a paraxial region thereof and animage-side surface 122 being concave in a paraxial region thereof. Thesecond lens element 120 is made of plastic material and has theobject-side surface 121 and the image-side surface 122 being bothaspheric.

The third lens element 130 with positive refractive power has anobject-side surface 131 being concave in a paraxial region thereof andan image-side surface 132 being convex in a paraxial region thereof. Thethird lens element 130 is made of plastic material and has theobject-side surface 131 and the image-side surface 132 being bothaspheric.

The fourth lens element 140 with positive refractive power has anobject-side surface 141 being convex in a paraxial region thereof and animage-side surface 142 being convex in a paraxial region thereof. Thefourth lens element 140 is made of plastic material and has theobject-side surface 141 and the image-side surface 142 being bothaspheric.

The fifth lens element 150 with negative refractive power has anobject-side surface 151 being concave in a paraxial region thereof andan image-side surface 152 being convex in a paraxial region thereof. Thefifth lens element 150 is made of plastic material and has theobject-side surface 151 and the image-side surface 152 being bothaspheric. The image-side surface 152 of the fifth lens element 150 hasat least one concave shape in an off-axis region thereof.

The sixth lens element 160 with positive refractive power has anobject-side surface 161 being convex in a paraxial region thereof and animage-side surface 162 being concave in a paraxial region thereof. Thesixth lens element 160 is made of plastic material and has theobject-side surface 161 and the image-side surface 162 being bothaspheric. The image-side surface 162 of the sixth lens element 160 hasat least one convex shape in an off-axis region thereof. The image-sidesurface 162 of the sixth lens element 160 has at least one inflectionpoint in an off-axis region thereof.

The IR-cut filter 170 is made of glass and located between the sixthlens element 160 and the image surface 180, and will not affect thefocal length of the lens system. The image sensor 190 is disposed on ornear the image surface 180 of the lens system.

The equation of the aspheric surface profiles of the aforementioned lenselements of the 1st embodiment is expressed as follows:

${{X(Y)} = {{\left( {Y^{2}/R} \right)/\left( {1 + {{sqrt}\left( {1 - {\left( {1 + k} \right) \times \left( {Y/R} \right)^{2}}} \right)}} \right)} + {\sum\limits_{i}\;{({Ai}) \times \left( Y^{i} \right)}}}},$

where,

X is the relative distance between a point on the aspheric surfacespaced at a distance Y from an optical axis and the tangential plane atthe aspheric surface vertex on the optical axis;

Y is the vertical distance from the point on the aspheric surface to theoptical axis;

R is the curvature radius;

k is the conic coefficient; and

Ai is the i-th aspheric coefficient, and in the embodiments, i may be,but is not limited to, 4, 6, 8, 10, 12, 14 and 16.

In the lens system of the image capturing unit according to the 1stembodiment, when a focal length of the lens system is f, an f-number ofthe lens system is Fno, and half of a maximal field of view of the lenssystem is HFOV, these parameters have the following values: f=1.38millimeters (mm); Fno=2.45; and HFOV=57.7 degrees (deg.).

When half of the maximal field of view of the lens system is HFOV, thefollowing condition is satisfied: tan(HFOV)=1.58.

When a maximum refractive index among the first lens element 110, thesecond lens element 120, the third lens element 130, the fourth lenselement 140, the fifth lens element 150 and the sixth lens element 160is Nmax, the following condition is satisfied: Nmax=1.650.

When an Abbe number of the second lens element 120 is V2, an Abbe numberof the fifth lens element 150 is V5, the following condition issatisfied: V2+V5=45.0.

When an axial distance between the stop 100 and the image-side surface162 of the sixth lens element 160 is SD, an axial distance between theobject-side surface 111 of the first lens element 110 and the image-sidesurface 162 of the sixth lens element 160 is TD, the following conditionis satisfied: SD/TD=0.75.

When an axial distance between the first lens element 110 and the secondlens element 120 is T12, an axial distance between the fourth lenselement 140 and the fifth lens element 150 is T45, the followingcondition is satisfied: T12/T45=7.93.

When an axial distance between the object-side surface 111 of the firstlens element 110 and the image surface 180 is TL, the followingcondition is satisfied: TL=4.19 mm.

When the axial distance between the object-side surface 111 of the firstlens element 110 and the image surface 180 is TL, a maximum image heightof the lens system is ImgH, the following condition is satisfied:TL/ImgH=2.31.

When the axial distance between the object-side surface 111 of the firstlens element 110 and the image surface 180 is TL, half of the maximalfield of view of the lens system is HFOV, the following condition issatisfied: TL/sin(1.6*HFOV)=4.20 mm.

When the focal length of the lens system is f, a curvature radius of theobject-side surface 121 of the second lens element 120 is R3, thefollowing condition is satisfied: f/R3=0.37.

When the focal length of the lens system is f, a curvature radius of animage-side surface of a lens element being the closest one to an imagesurface among all lens elements with refractive power is RL, thefollowing condition is satisfied: f/RL=0.84. In this embodiment, thelens element being the closest one to an image surface among all lenselements with refractive power is the sixth lens element 160, so thatthe curvature radius of the image-side surface 162 of the sixth lenselement 160 is RL.

When the focal length of the lens system is f, an entrance pupildiameter of the lens system is EPD, the following condition issatisfied: f/EPD=2.45.

When a focal length of the first lens element 110 is f1, a focal lengthof the second lens element 120 is f2, the following condition issatisfied: |f1/f2|=0.01.

When a focal length of the third lens element 130 is f3, a focal lengthof the fourth lens element 140 is f4, the following condition issatisfied: f3/f4=2.50.

When the focal length of the lens system is f, the focal length of thethird lens element 130 is f3, the focal length of the fourth lenselement 140 is f4, the following condition is satisfied:(f/f3)+(f/f4)=1.77.

When a maximum effective radius of the object-side surface 111 of thefirst lens element 110 is SD11, a maximum effective radius of theimage-side surface 162 of the sixth lens element 160 is SD62, thefollowing condition is satisfied: |SD11/SD62|=0.77. (In this embodiment,the maximum effective radius of the object-side surface 111 of the firstlens element 110 is also defined as SDfs, and the maximum effectiveradius of the image-side surface 162 of the sixth lens element 160 isalso defined as SDls. Therefore, the following condition is satisfied:|SDfs/SDls|=0.77.)

The detailed optical data of the 1st embodiment are shown in Table 1 andthe aspheric surface data are shown in Table 2 below.

TABLE 1 1st Embodiment f = 1.38 mm, Fno = 2.45, HFOV = 57.7 deg. FocalSurface # Curvature Radius Thickness Material Index Abbe # Length 0Object Plano Infinity 1 Lens 1 −14.847 (ASP) 0.240 Plastic 1.514 56.8−2.61 2 1.481 (ASP) 0.629 3 Ape. Stop Plano 0.013 4 Lens 2 3.731 (ASP)0.220 Plastic 1.650 21.5 230.77 5 3.737 (ASP) 0.051 6 Lens 3 −2.993(ASP) 0.427 Plastic 1.544 55.9 2.73 7 −1.043 (ASP) 0.035 8 Lens 4 1.360(ASP) 0.741 Plastic 1.544 55.9 1.09 9 −0.855 (ASP) 0.081 10 Lens 5−0.580 (ASP) 0.250 Plastic 1.639 23.5 −1.41 11 −1.913 (ASP) 0.411 12Lens 6 1.683 (ASP) 0.358 Plastic 1.639 23.5 46.04 13 1.637 (ASP) 0.35014 IR-cut filter Plano 0.210 Glass 1.517 64.2 — 15 Plano 0.176 16 ImagePlano — Note: Reference wavelength is 587.6 nm (d-line). Effectiveradius of Surface 10 is 0.880 mm.

TABLE 2 Aspheric Coefficients Surface # 1 2 4 5 6 7 k = −1.0000E+00−4.8502E+01 −5.0000E+01 −9.0000E+01 −1.0304E+01 −6.5826E−01 A4 =9.6006E−01 2.6386E+00 −5.5614E−01 1.8541E−01 7.4920E−01 −1.2400E+00 A6 =−2.0471E+00 −7.8023E+00 −4.1588E+00 −3.2258E+00 −4.7732E−01 8.8325E+00A8 = 3.4102E+00 1.9121E+01 1.5111E+01 4.8820E+00 5.1562E+00 −3.8482E+01A10 = −3.4988E+00 −1.8369E+01 −7.3505E+01 −3.0208E−01 −1.8503E+019.6977E+01 A12 = 1.9497E+00 — — −3.2919E+01 2.0568E+01 −8.5090E+01 A14 =−4.5815E−01 — — — — — Surface # 8 9 10 11 12 13 k = −3.7471E+01−1.6551E−01 −3.6879E+00 −1.2850E+00 −9.0000E+01 −1.0000E+00 A4 =3.6186E−01 1.8905E+00 1.7988E+00 1.0507E+00 5.4696E−01 −1.1850E−01 A6 =−8.9405E−01 −6.8344E+00 −7.0604E+00 −1.2741E+00 −5.0932E+00 −7.3790E−01A8 = 1.3113E+00 1.3503E+01 1.3558E+01 4.1042E−01 1.5722E+01 1.6876E+00A10 = −6.6689E−01 −1.3341E+01 −1.6084E+01 4.2292E−01 −2.8627E+01−1.9974E+00 A12 = — 6.0705E+00 1.1554E+01 −4.4054E−01 3.0503E+011.3321E+00 A14 = — — −3.5506E+00 1.1692E−01 −1.7360E+01 −4.7199E−01 A16= — — — — 3.9876E+00 6.8730E−02

In Table 1, the curvature radius, the thickness and the focal length areshown in millimeters (mm). Surface numbers 0-16 represent the surfacessequentially arranged from the object-side to the image-side along theoptical axis. In Table 2, k represents the conic coefficient of theequation of the aspheric surface profiles. A4-A16 represent the asphericcoefficients ranging from the 4th order to the 16th order. The tablespresented below for each embodiment are the corresponding schematicparameter and aberration curves, and the definitions of the tables arethe same as Table 1 and Table 2 of the 1st embodiment. Therefore, anexplanation in this regard will not be provided again.

2nd Embodiment

FIG. 3 is a schematic view of an image capturing unit according to the2nd embodiment of the present disclosure. FIG. 4 shows, in order fromleft to right, spherical aberration curves, astigmatic field curves anda distortion curve of the image capturing unit according to the 2ndembodiment. In FIG. 3, the image capturing unit includes the lens system(its reference numeral is omitted) of the present disclosure and animage sensor 290. The lens system includes, in order from an object sideto an image side, a first lens element 210, an aperture stop 200, asecond lens element 220, a third lens element 230, a fourth lens element240, a fifth lens element 250, a sixth lens element 260, an IR-cutfilter 270 and an image surface 280, wherein the lens system has a totalof six non-cemented lens elements (210-260) with refractive power. Thereis an air gap in a paraxial region between every two of the first lenselement 210, the second lens element 220, the third lens element 230,the fourth lens element 240, the fifth lens element 250 and the sixthlens element 260 that are adjacent to each other. In this embodiment,the first lens element 210 is an object-side lens element being theclosest lens element to an imaged object among all lens elements withrefractive power, and the sixth lens element 260 is an image-side lenselement being the closest lens element to the image surface 280 amongall lens elements with refractive power.

The first lens element 210 with negative refractive power has anobject-side surface 211 being convex in a paraxial region thereof and animage-side surface 212 being concave in a paraxial region thereof. Thefirst lens element 210 is made of plastic material and has theobject-side surface 211 and the image-side surface 212 being bothaspheric.

The second lens element 220 with negative refractive power has anobject-side surface 221 being convex in a paraxial region thereof and animage-side surface 222 being concave in a paraxial region thereof. Thesecond lens element 220 is made of plastic material and has theobject-side surface 221 and the image-side surface 222 being bothaspheric.

The third lens element 230 with positive refractive power has anobject-side surface 231 being concave in a paraxial region thereof andan image-side surface 232 being convex in a paraxial region thereof. Thethird lens element 230 is made of plastic material and has theobject-side surface 231 and the image-side surface 232 being bothaspheric.

The fourth lens element 240 with positive refractive power has anobject-side surface 241 being convex in a paraxial region thereof and animage-side surface 242 being convex in a paraxial region thereof. Thefourth lens element 240 is made of plastic material and has theobject-side surface 241 and the image-side surface 242 being bothaspheric.

The fifth lens element 250 with negative refractive power has anobject-side surface 251 being concave in a paraxial region thereof andan image-side surface 252 being convex in a paraxial region thereof. Thefifth lens element 250 is made of plastic material and has theobject-side surface 251 and the image-side surface 252 being bothaspheric. The image-side surface 252 of the fifth lens element 250 hasat least one concave shape in an off-axis region thereof.

The sixth lens element 260 with positive refractive power has anobject-side surface 261 being convex in a paraxial region thereof and animage-side surface 262 being concave in a paraxial region thereof. Thesixth lens element 260 is made of plastic material and has theobject-side surface 261 and the image-side surface 262 being bothaspheric. The image-side surface 262 of the sixth lens element 260 hasat least one convex shape in an off-axis region thereof. The image-sidesurface 262 of the sixth lens element 260 has at least one inflectionpoint in an off-axis region thereof.

The IR-cut filter 270 is made of glass and located between the sixthlens element 260 and the image surface 280, and will not affect thefocal length of the lens system. The image sensor 290 is disposed on ornear the image surface 280 of the lens system.

The detailed optical data of the 2nd embodiment are shown in Table 3 andthe aspheric surface data are shown in Table 4 below.

TABLE 3 2nd Embodiment f = 1.27 mm, Fno = 2.38, HFOV = 55.0 deg. FocalSurface # Curvature Radius Thickness Material Index Abbe # Length 0Object Plano Infinity 1 Lens 1 10.249 (ASP) 0.240 Plastic 1.544 55.9−3.45 2 1.573 (ASP) 0.676 3 Ape. Stop Plano 0.015 4 Lens 2 3.410 (ASP)0.216 Plastic 1.633 23.4 −13.38 5 2.371 (ASP) 0.048 6 Lens 3 −6.501(ASP) 0.463 Plastic 1.544 55.9 1.83 7 −0.883 (ASP) 0.035 8 Lens 4 1.968(ASP) 0.590 Plastic 1.544 55.9 1.17 9 −0.843 (ASP) 0.162 10 Lens 5−0.349 (ASP) 0.250 Plastic 1.633 23.4 −0.93 11 −1.091 (ASP) 0.339 12Lens 6 0.714 (ASP) 0.256 Plastic 1.544 55.9 1.93 13 1.960 (ASP) 0.350 14IR-cut filter Plano 0.210 Glass 1.517 64.2 — 15 Plano 0.246 16 ImagePlano — Note: Reference wavelength is 587.6 nm (d-line).

TABLE 4 Aspheric Coefficients Surface # 1 2 4 5 6 7 k = −1.0000E+00−4.4496E+01 −3.1114E+01 −3.7751E+01 −2.5526E+00 −7.7429E−01 A4 =8.6327E−01 2.1618E+00 −8.9777E−01 −1.5737E−02 5.3929E−01 −1.2241E+00 A6= −1.6889E+00 −6.1795E+00 −4.1560E+00 −3.6520E+00 −6.3771E−01 8.6909E+00A8 = 2.0138E+00 1.2752E+01 2.4640E+01 6.5791E+00 5.0817E+00 −3.8944E+01A10 = −9.6607E−01 −1.9248E+01 −1.7759E+02 1.4561E+00 −1.3467E+019.7362E+01 A12 = −5.1757E−01 3.0029E+01 −1.7440E−12 −6.1967E+011.3258E+01 −8.1776E+01 A14 = 8.6486E−01 −3.9427E+01 — −3.1787E−13 — —A16 = −3.1387E−01 2.1191E+01 — — — — Surface # 8 9 10 11 12 13 k =−8.9679E+01 −1.5889E−01 −2.8197E+00 −4.4558E−01 −9.3513E+00 −1.1324E+01A4 = 1.9930E−01 2.2065E+00 2.0327E+00 1.2142E+00 9.4140E−01 6.3442E−01A6 = −5.9724E−01 −6.9258E+00 −7.0631E+00 −1.2482E+00 −6.0599E+00−1.9021E+00 A8 = 1.0035E+00 1.3331E+01 1.3473E+01 4.0414E−01 1.5863E+012.7268E+00 A10 = −7.3762E−01 −1.3476E+01 −1.6291E+01 4.0739E−01−2.5124E+01 −2.5667E+00 A12 = −2.5313E−02 5.8272E+00 1.1315E+01−4.5463E−01 2.3415E+01 1.5276E+00 A14 = — — −3.6326E+00 1.3108E−01−1.1731E+01 −5.1705E−01 A16 = — — — — 2.4196E+00 7.4633E−02

In the 2nd embodiment, the equation of the aspheric surface profiles ofthe aforementioned lens elements is the same as the equation of the 1stembodiment. Also, the definitions of these parameters shown in thefollowing table are the same as those stated in the 1st embodiment withcorresponding values for the 2nd embodiment, so an explanation in thisregard will not be provided again.

Moreover, these parameters can be calculated from Table 3 and Table 4 asthe following values and satisfy the following conditions:

2nd Embodiment f [mm] 1.27 TL/ImgH 2.26 Fno 2.38 TL/sin(1.6 * HFOV) [mm]4.10 HFOV [deg.] 55.0 f/R3 0.37 tan(HFOV) 1.43 f/RL 0.65 Nmax 1.633|f1/f2| 0.26 V2 + V5 46.7 f3/f4 1.56 SD/TD 0.72 (f/f3) + (f/f4) 1.78T12/T45 4.27 |SD11/SD62| 0.77 TL [mm] 4.10 f/EPD 2.38

3rd Embodiment

FIG. 5 is a schematic view of an image capturing unit according to the3rd embodiment of the present disclosure. FIG. 6 shows, in order fromleft to right, spherical aberration curves, astigmatic field curves anda distortion curve of the image capturing unit according to the 3rdembodiment. In FIG. 5, the image capturing unit includes the lens system(its reference numeral is omitted) of the present disclosure and animage sensor 390. The lens system includes, in order from an object sideto an image side, a first lens element 310, an aperture stop 300, asecond lens element 320, a third lens element 330, a fourth lens element340, a fifth lens element 350, a sixth lens element 360, an IR-cutfilter 370 and an image surface 380, wherein the lens system has a totalof six non-cemented lens elements (310-360) with refractive power. Thereis an air gap in a paraxial region between every two of the first lenselement 310, the second lens element 320, the third lens element 330,the fourth lens element 340, the fifth lens element 350 and the sixthlens element 360 that are adjacent to each other. In this embodiment,the first lens element 310 is an object-side lens element being theclosest lens element to an imaged object among all lens elements withrefractive power, and the sixth lens element 360 is an image-side lenselement being the closest lens element to the image surface 380 amongall lens elements with refractive power.

The first lens element 310 with negative refractive power has anobject-side surface 311 being concave in a paraxial region thereof andan image-side surface 312 being concave in a paraxial region thereof.The first lens element 310 is made of plastic material and has theobject-side surface 311 and the image-side surface 312 being bothaspheric.

The second lens element 320 with negative refractive power has anobject-side surface 321 being convex in a paraxial region thereof and animage-side surface 322 being concave in a paraxial region thereof. Thesecond lens element 320 is made of plastic material and has theobject-side surface 321 and the image-side surface 322 being bothaspheric.

The third lens element 330 with positive refractive power has anobject-side surface 331 being concave in a paraxial region thereof andan image-side surface 332 being convex in a paraxial region thereof. Thethird lens element 330 is made of plastic material and has theobject-side surface 331 and the image-side surface 332 being bothaspheric.

The fourth lens element 340 with positive refractive power has anobject-side surface 341 being convex in a paraxial region thereof and animage-side surface 342 being convex in a paraxial region thereof. Thefourth lens element 340 is made of plastic material and has theobject-side surface 341 and the image-side surface 342 being bothaspheric.

The fifth lens element 350 with negative refractive power has anobject-side surface 351 being concave in a paraxial region thereof andan image-side surface 352 being convex in a paraxial region thereof. Thefifth lens element 350 is made of plastic material and has theobject-side surface 351 and the image-side surface 352 being bothaspheric. The image-side surface 352 of the fifth lens element 350 hasat least one concave shape in an off-axis region thereof.

The sixth lens element 360 with negative refractive power has anobject-side surface 361 being convex in a paraxial region thereof and animage-side surface 362 being concave in a paraxial region thereof. Thesixth lens element 360 is made of plastic material and has theobject-side surface 361 and the image-side surface 362 being bothaspheric. The image-side surface 362 of the sixth lens element 360 hasat least one convex shape in an off-axis region thereof. The image-sidesurface 362 of the sixth lens element 360 has at least one inflectionpoint in an off-axis region thereof.

The IR-cut filter 370 is made of glass and located between the sixthlens element 360 and the image surface 380, and will not affect thefocal length of the lens system. The image sensor 390 is disposed on ornear the image surface 380 of the lens system.

The detailed optical data of the 3rd embodiment are shown in Table 5 andthe aspheric surface data are shown in Table 6 below.

TABLE 5 3rd Embodiment f = 1.55 mm, Fno = 2.29, HFOV = 59.9 deg. FocalSurface # Curvature Radius Thickness Material Index Abbe # Length 0Object Plano Infinity 1 Lens 1 −107.021 (ASP) 0.238 Plastic 1.544 55.9−2.20 2 1.209 (ASP) 0.287 3 Ape. Stop Plano 0.006 4 Lens 2 2.425 (ASP)0.220 Plastic 1.639 23.5 −19.77 5 1.962 (ASP) 0.050 6 Lens 3 −15.680(ASP) 0.481 Plastic 1.544 55.9 1.66 7 −0.861 (ASP) 0.035 8 Lens 4 1.997(ASP) 0.789 Plastic 1.544 55.9 1.27 9 −0.908 (ASP) 0.052 10 Lens 5−0.645 (ASP) 0.268 Plastic 1.639 23.5 −1.67 11 −1.891 (ASP) 0.317 12Lens 6 1.317 (ASP) 0.368 Plastic 1.639 23.5 −10.00 13 0.973 (ASP) 0.40014 IR-cut filter Plano 0.110 Glass 1.517 64.2 — 15 Plano 0.293 16 ImagePlano — Note: Reference wavelength is 587.6 nm (d-line). Effectiveradius of Surface 10 is 0.860 mm.

TABLE 6 Aspheric Coefficients Surface # 1 2 4 5 6 7 k = −5.0000E+01−2.4772E+01 −4.3022E+01 −4.2722E+01 −6.5636E+01 −1.8277E+00 A4 =5.7783E−01 2.6199E+00 −6.0117E−01 2.2233E−01 3.5084E−01 −5.1274E−01 A6 =−1.1144E+00 −9.8086E+00 −1.8266E+00 −5.0058E+00 3.1549E−02 2.7517E+00 A8= 1.8973E+00 3.3530E+01 −2.0273E+00 2.0124E+01 3.8172E+00 −1.4107E+01A10 = −1.7463E+00 −2.3977E+01 −7.8015E+00 −5.0341E+01 −1.2742E+014.0183E+01 A12 = 5.6591E−01 −6.2273E+01 — 4.3927E+01 1.2565E+01−3.4622E+01 A14 = 7.6589E−02 — — — — — Surface # 8 9 10 11 12 13 k =−3.0993E+01 −1.3475E−01 −6.4865E+00 −6.5987E+01 −1.1488E+00 −4.6286E+00A4 = 3.3391E−01 1.9183E+00 1.3786E+00 6.2922E−01 −5.7596E−01 −1.4289E−01A6 = −5.7815E−01 −6.7169E+00 −4.3432E+00 −2.0853E−01 3.9882E−01−1.1526E−01 A8 = 6.7678E−01 1.1961E+01 4.5193E+00 −1.2896E+00−4.8294E−01 2.8707E−01 A10 = −1.2090E−01 −1.0209E+01 5.6027E−012.2436E+00 5.6436E−01 −2.8855E−01 A12 = −1.9575E−01 3.8010E+00−4.7488E+00 −1.5595E+00 −3.1479E−01 1.5861E−01 A14 = — — 2.7586E+004.1908E−01 7.7413E−03 −4.7377E−02 A16 = — — — — 3.7519E−02 5.9462E−03

In the 3rd embodiment, the equation of the aspheric surface profiles ofthe aforementioned lens elements is the same as the equation of the 1stembodiment. Also, the definitions of these parameters shown in thefollowing table are the same as those stated in the 1st embodiment withcorresponding values for the 3rd embodiment, so an explanation in thisregard will not be provided again.

Moreover, these parameters can be calculated from Table 5 and Table 6 asthe following values and satisfy the following conditions:

3rd Embodiment f [mm] 1.55 TL/ImgH 2.16 Fno 2.29 TL/sin(1.6 * HFOV) [mm]3.93 HFOV [deg.] 59.9 f/R3 0.64 tan(HFOV) 1.73 f/RL 1.59 Nmax 1.639|f1/f2| 0.11 V2 + V5 47.0 f3/f4 1.31 SD/TD 0.83 (f/f3) + (f/f4) 2.15T12/T45 5.63 |SD11/SD62| 0.59 TL [mm] 3.91 f/EPD 2.29

4th Embodiment

FIG. 7 is a schematic view of an image capturing unit according to the4th embodiment of the present disclosure. FIG. 8 shows, in order fromleft to right, spherical aberration curves, astigmatic field curves anda distortion curve of the image capturing unit according to the 4thembodiment. In FIG. 7, the image capturing unit includes the lens system(its reference numeral is omitted) of the present disclosure and animage sensor 490. The lens system includes, in order from an object sideto an image side, a first lens element 410, an aperture stop 400, asecond lens element 420, a third lens element 430, a fourth lens element440, a fifth lens element 450, a sixth lens element 460, an IR-cutfilter 470 and an image surface 480, wherein the lens system has a totalof six non-cemented lens elements (410-460) with refractive power. Thereis an air gap in a paraxial region between every two of the first lenselement 410, the second lens element 420, the third lens element 430,the fourth lens element 440, the fifth lens element 450 and the sixthlens element 460 that are adjacent to each other. In this embodiment,the first lens element 410 is an object-side lens element being theclosest lens element to an imaged object among all lens elements withrefractive power, and the sixth lens element 460 is an image-side lenselement being the closest lens element to the image surface 480 amongall lens elements with refractive power.

The first lens element 410 with negative power has an object-sidesurface 411 being convex in a paraxial region thereof and an image-sidesurface 412 being concave in a paraxial region thereof. The first lenselement 410 is made of plastic material and has the object-side surface411 and the image-side surface 412 being both aspheric.

The second lens element 420 with positive refractive power has anobject-side surface 421 being convex in a paraxial region thereof and animage-side surface 422 being concave in a paraxial region thereof. Thesecond lens element 420 is made of plastic material and has theobject-side surface 421 and the image-side surface 422 being bothaspheric.

The third lens element 430 with positive refractive power has anobject-side surface 431 being concave in a paraxial region thereof andan image-side surface 432 being convex in a paraxial region thereof. Thethird lens element 430 is made of plastic material and has theobject-side surface 431 and the image-side surface 432 being bothaspheric.

The fourth lens element 440 with positive refractive power has anobject-side surface 441 being convex in a paraxial region thereof and animage-side surface 442 being convex in a paraxial region thereof. Thefourth lens element 440 is made of plastic material and has theobject-side surface 441 and the image-side surface 442 being bothaspheric.

The fifth lens element 450 with negative refractive power has anobject-side surface 451 being concave in a paraxial region thereof andan image-side surface 452 being convex in a paraxial region thereof. Thefifth lens element 450 is made of plastic material and has theobject-side surface 451 and the image-side surface 452 being bothaspheric. The image-side surface 452 of the fifth lens element 450 hasat least one concave shape in an off-axis region thereof.

The sixth lens element 460 with negative refractive power has anobject-side surface 461 being convex in a paraxial region thereof and animage-side surface 462 being concave in a paraxial region thereof. Thesixth lens element 460 is made of plastic material and has theobject-side surface 461 and the image-side surface 462 being bothaspheric. The image-side surface 462 of the sixth lens element 460 hasat least one convex shape in an off-axis region thereof. The image-sidesurface 462 of the sixth lens element 460 has at least one inflectionpoint in an off-axis region thereof.

The IR-cut filter 470 is made of glass and located between the sixthlens element 460 and the image surface 480, and will not affect thefocal length of the lens system. The image sensor 490 is disposed on ornear the image surface 480 of the lens system.

The detailed optical data of the 4th embodiment are shown in Table 7 andthe aspheric surface data are shown in Table 8 below.

TABLE 7 4th Embodiment f = 1.54 mm, Fno = 2.29, HFOV = 60.0 deg. FocalSurface # Curvature Radius Thickness Material Index Abbe # Length 0Object Plano Infinity 1 Lens 1 50.000 (ASP) 0.240 Plastic 1.544 55.9−2.23 2 1.181 (ASP) 0.293 3 Ape. Stop Plano 0.010 4 Lens 2 2.639 (ASP)0.220 Plastic 1.639 23.5 51.87 5 2.774 (ASP) 0.051 6 Lens 3 −4.127 (ASP)0.465 Plastic 1.544 55.9 2.17 7 −0.956 (ASP) 0.035 8 Lens 4 1.515 (ASP)0.773 Plastic 1.544 55.9 1.16 9 −0.890 (ASP) 0.038 10 Lens 5 −0.668(ASP) 0.270 Plastic 1.639 23.5 −1.63 11 −2.156 (ASP) 0.313 12 Lens 61.328 (ASP) 0.370 Plastic 1.639 23.5 −9.69 13 0.975 (ASP) 0.350 14IR-cut filter Plano 0.110 Glass 1.517 64.2 — 15 Plano 0.358 16 ImagePlano — — Note: Reference wavelength is 587.6 nm (d-line). Effectiveradius of Surface 5 is 0.490 mm.

TABLE 8 Aspheric Coefficients Surface # 1 2 4 5 6 7 k = −4.9011E+01−2.0621E+01 −4.8339E+01 −6.4255E+01 −5.0113E+01 −1.0070E+00 A4 =5.6109E−01 2.3911E+00 −3.5700E−01 2.9359E−01 7.1587E−01 −1.1660E+00 A6 =−1.1316E+00 −8.0896E+00 −5.7842E+00 −3.8064E+00 −9.8477E−01 8.6446E+00A8 = 2.0910E+00 2.8735E+01 2.1503E+01 3.6669E+00 4.7254E+00 −3.9024E+01A10 = −2.4154E+00 −4.2951E+01 −7.6304E+01 1.5649E+01 −1.1835E+019.5133E+01 A12 = 1.4816E+00 — — −6.0684E+01 8.9285E+00 −8.2021E+01 A14 =−3.3837E−01 — — — — — Surface # 8 9 10 11 12 13 k = −5.1447E+01−1.5388E−01 −5.7723E+00 −8.9272E+01 −2.3149E+00 −1.2970E+00 A4 =3.9804E−01 1.9103E+00 1.8678E+00 9.6266E−01 −3.0656E−01 −4.6798E−01 A6 =−9.2296E−01 −6.9733E+00 −7.0614E+00 −1.2389E+00 −1.4750E−01 2.5699E−01A8 = 1.3404E+00 1.3533E+01 1.3428E+01 4.3373E−01 3.8860E−01 −6.2075E−02A10 = −6.0566E−01 −1.3302E+01 −1.6175E+01 4.3077E−01 −1.3541E−01−2.7441E−02 A12 = — 6.0578E+00 1.1544E+01 −4.4103E−01 −1.2050E−012.7972E−02 A14 = — — −3.5418E+00 1.1234E−01 1.0542E−01 −9.7056E−03 A16 =— — — — −2.2817E−02 1.3088E−03

In the 4th embodiment, the equation of the aspheric surface profiles ofthe aforementioned lens elements is the same as the equation of the 1stembodiment. Also, the definitions of these parameters shown in thefollowing table are the same as those stated in the 1st embodiment withcorresponding values for the 4th embodiment, so an explanation in thisregard will not be provided again.

Moreover, these parameters can be calculated from Table 7 and Table 8 asthe following values and satisfy the following conditions:

4th Embodiment f [mm] 1.54 TL/ImgH 2.15 Fno 2.29 TL/sin(1.6 * HFOV) [mm]3.92 HFOV [deg.] 60.0 f/R3 0.58 tan(HFOV) 1.73 f/RL 1.58 Nmax 1.639|f1/f2| 0.04 V2 + V5 47.0 f3/f4 1.87 SD/TD 0.83 (f/f3) + (f/f4) 2.04T12/T45 7.97 |SD11/SD62| 0.58 TL [mm] 3.90 f/EPD 2.29

5th Embodiment

FIG. 9 is a schematic view of an image capturing unit according to the5th embodiment of the present disclosure. FIG. 10 shows, in order fromleft to right, spherical aberration curves, astigmatic field curves anda distortion curve of the image capturing unit according to the 5thembodiment. In FIG. 9, the image capturing unit includes the lens system(its reference numeral is omitted) of the present disclosure and animage sensor 590. The lens system includes, in order from an object sideto an image side, a first lens element 510, an aperture stop 500, asecond lens element 520, a third lens element 530, a fourth lens element540, a fifth lens element 550, a sixth lens element 560, an IR-cutfilter 570 and an image surface 580, wherein the lens system has a totalof six non-cemented lens elements (510-560) with refractive power. Thereis an air gap in a paraxial region between every two of the first lenselement 510, the second lens element 520, the third lens element 530,the fourth lens element 540, the fifth lens element 550 and the sixthlens element 560 that are adjacent to each other. In this embodiment,the first lens element 510 is an object-side lens element being theclosest lens element to an imaged object among all lens elements withrefractive power, and the sixth lens element 560 is an image-side lenselement being the closest lens element to the image surface 580 amongall lens elements with refractive power.

The first lens element 510 with negative refractive power has anobject-side surface 511 being convex in a paraxial region thereof and animage-side surface 512 being concave in a paraxial region thereof. Thefirst lens element 510 is made of plastic material and has theobject-side surface 511 and the image-side surface 512 being bothaspheric.

The second lens element 520 with positive refractive power has anobject-side surface 521 being convex in a paraxial region thereof and animage-side surface 522 being convex in a paraxial region thereof. Thesecond lens element 520 is made of plastic material and has theobject-side surface 521 and the image-side surface 522 being bothaspheric.

The third lens element 530 with positive refractive power has anobject-side surface 531 being concave in a paraxial region thereof andan image-side surface 532 being convex in a paraxial region thereof. Thethird lens element 530 is made of plastic material and has theobject-side surface 531 and the image-side surface 532 being bothaspheric.

The fourth lens element 540 with positive refractive power has anobject-side surface 541 being convex in a paraxial region thereof and animage-side surface 542 being convex in a paraxial region thereof. Thefourth lens element 540 is made of plastic material and has theobject-side surface 541 and the image-side surface 542 being bothaspheric.

The fifth lens element 550 with negative refractive power has anobject-side surface 551 being concave in a paraxial region thereof andan image-side surface 552 being convex in a paraxial region thereof. Thefifth lens element 550 is made of plastic material and has theobject-side surface 551 and the image-side surface 552 being bothaspheric. The image-side surface 552 of the fifth lens element 550 hasat least one concave shape in an off-axis region thereof.

The sixth lens element 560 with positive refractive power has anobject-side surface 561 being convex in a paraxial region thereof and animage-side surface 562 being concave in a paraxial region thereof. Thesixth lens element 560 is made of plastic material and has theobject-side surface 561 and the image-side surface 562 being bothaspheric. The image-side surface 562 of the sixth lens element 560 hasat least one convex shape in an off-axis region thereof. The image-sidesurface 562 of the sixth lens element 560 has at least one inflectionpoint in an off-axis region thereof.

The IR-cut filter 570 is made of glass and located between the sixthlens element 560 and the image surface 580, and will not affect thefocal length of the lens system. The image sensor 590 is disposed on ornear the image surface 580 of the lens system.

The detailed optical data of the 5th embodiment are shown in Table 9 andthe aspheric surface data are shown in Table 10 below.

TABLE 9 5th Embodiment f = 1.29 mm, Fno = 2.45, HFOV = 54.0 deg. FocalSurface # Curvature Radius Thickness Material Index Abbe # Length 0Object Plano Infinity 1 Lens 1 6.615 (ASP) 0.244 Plastic 1.540 42.1−3.09 2 1.316 (ASP) 0.691 3 Ape. Stop Plano 0.002 4 Lens 2 2.738 (ASP)0.277 Plastic 1.544 55.9 3.83 6 −8.422 (ASP) 0.060 7 Lens 3 −1.475 (ASP)0.371 Plastic 1.544 55.9 2.40 8 −0.754 (ASP) 0.035 9 Lens 4 4.179 (ASP)0.638 Plastic 1.544 55.9 1.26 10 −0.777 (ASP) 0.119 11 Lens 5 −0.431(ASP) 0.253 Plastic 1.639 23.5 −1.15 12 −1.284 (ASP) 0.483 13 Lens 61.447 (ASP) 0.230 Plastic 1.583 30.2 2.52 14 96.670 (ASP) 0.300 15IR-cut filter Plano 0.210 Glass 1.517 64.2 — 16 Plano 0.191 17 ImagePlano — Note: Reference wavelength is 587.6 nm (d-line).

TABLE 10 Aspheric Coefficients Surface # 1 2 4 5 6 7 k = −1.0000E+00−1.0000E+00 −5.5714E+00 −1.0000E+00 −3.3782E+00 −5.9623E+00 A4 =1.3042E+00 2.0913E+00 −4.7083E−01 −3.3635E−02 4.7592E−01 −1.4001E+00 A6= −3.5188E+00 −6.8313E+00 −3.1777E+00 −2.8004E+00 −5.1539E−01 8.1368E+00A8 = 6.9557E+00 1.8671E+01 2.2051E+01 7.9156E+00 5.6121E+00 −3.7307E+01A10 = −8.3121E+00 −1.9461E+01 −1.7398E+02 −4.8884E+01 −6.3227E+001.0007E+02 A12 = 5.3275E+00 — — 7.9828E+01 2.1290E+00 −9.0794E+01 A14 =−1.4262E+00 — — — — — Surface # 8 9 10 11 12 13 k = −1.0000E+00−3.2940E−01 −2.9626E+00 −1.2040E+00 −9.0000E+01 −9.0000E+01 A4 =1.6237E−01 2.0604E+00 1.9111E+00 1.0629E+00 1.2332E+00 1.3023E+00 A6 =−8.0985E−01 −6.8144E+00 −7.2094E+00 −1.2607E+00 −8.3004E+00 −4.7428E+00A8 = 1.2045E+00 1.3336E+01 1.3476E+01 4.1482E−01 1.8889E+01 7.9016E+00A10 = −9.3748E−01 −1.3615E+01 −1.6095E+01 4.2085E−01 −2.5557E+01−7.9314E+00 A12 = — 5.9681E+00 1.1565E+01 −4.4369E−01 2.2115E+014.8283E+00 A14 = — — −3.5417E+00 1.2445E−01 −1.1250E+01 −1.6420E+00 A16= — — — — 2.4957E+00 2.3818E−01

In the 5th embodiment, the equation of the aspheric surface profiles ofthe aforementioned lens elements is the same as the equation of the 1stembodiment. Also, the definitions of these parameters shown in thefollowing table are the same as those stated in the 1st embodiment withcorresponding values for the 5th embodiment, so an explanation in thisregard will not be provided again.

Moreover, these parameters can be calculated from Table 9 and Table 10as the following values and satisfy the following conditions:

5th Embodiment f [mm] 1.29 TL/ImgH 2.26 Fno 2.45 TL/sin(1.6 * HFOV) [mm]4.11 HFOV [deg.] 54.0 f/R3 0.47 tan(HFOV) 1.38 f/RL 0.01 Nmax 1.639|f1/f2| 0.81 V2 + V5 79.4 f3/f4 1.90 SD/TD 0.73 (f/f3) + (f/f4) 1.56T12/T45 5.82 |SD11/SD62| 0.74 TL [mm] 4.10 f/EPD 2.45

6th Embodiment

FIG. 11 is a schematic view of an image capturing unit according to the6th embodiment of the present disclosure. FIG. 12 shows, in order fromleft to right, spherical aberration curves, astigmatic field curves anda distortion curve of the image capturing unit according to the 6thembodiment. In FIG. 11, the image capturing unit includes the lenssystem (its reference numeral is omitted) of the present disclosure andan image sensor 690. The lens system includes, in order from an objectside to an image side, a first lens element 610, an aperture stop 600, asecond lens element 620, a third lens element 630, a fourth lens element640, a fifth lens element 650, a sixth lens element 660, an IR-cutfilter 670 and an image surface 680, wherein the lens system has a totalof six non-cemented lens elements (610-660) with refractive power. Thereis an air gap in a paraxial region between every two of the first lenselement 610, the second lens element 620, the third lens element 630,the fourth lens element 640, the fifth lens element 650 and the sixthlens element 660 that are adjacent to each other. In this embodiment,the first lens element 610 is an object-side lens element being theclosest lens element to an imaged object among all lens elements withrefractive power, and the sixth lens element 660 is an image-side lenselement being the closest lens element to the image surface 680 amongall lens elements with refractive power.

The first lens element 610 with negative refractive power has anobject-side surface 611 being concave in a paraxial region thereof andan image-side surface 612 being concave in a paraxial region thereof.The first lens element 610 is made of plastic material and has theobject-side surface 611 and the image-side surface 612 being bothaspheric.

The second lens element 620 with negative refractive power has anobject-side surface 621 being convex in a paraxial region thereof and animage-side surface 622 being concave in a paraxial region thereof. Thesecond lens element 620 is made of plastic material and has theobject-side surface 621 and the image-side surface 622 being bothaspheric.

The third lens element 630 with positive refractive power has anobject-side surface 631 being convex in a paraxial region thereof and animage-side surface 632 being convex in a paraxial region thereof. Thethird lens element 630 is made of plastic material and has theobject-side surface 631 and the image-side surface 632 being bothaspheric.

The fourth lens element 640 with positive refractive power has anobject-side surface 641 being convex in a paraxial region thereof and animage-side surface 642 being convex in a paraxial region thereof. Thefourth lens element 640 is made of plastic material and has theobject-side surface 641 and the image-side surface 642 being bothaspheric.

The fifth lens element 650 with negative refractive power has anobject-side surface 651 being concave in a paraxial region thereof andan image-side surface 652 being convex in a paraxial region thereof. Thefifth lens element 650 is made of plastic material and has theobject-side surface 651 and the image-side surface 652 being bothaspheric. The image-side surface 652 of the fifth lens element 650 hasat least one concave shape in an off-axis region thereof.

The sixth lens element 660 with positive refractive power has anobject-side surface 661 being convex in a paraxial region thereof and animage-side surface 662 being concave in a paraxial region thereof. Thesixth lens element 660 is made of plastic material and has theobject-side surface 661 and the image-side surface 662 being bothaspheric. The image-side surface 662 of the sixth lens element 660 hasat least one convex shape in an off-axis region thereof. The image-sidesurface 662 of the sixth lens element 660 has at least one inflectionpoint in an off-axis region thereof.

The IR-cut filter 670 is made of glass and located between the sixthlens element 660 and the image surface 680, and will not affect thefocal length of the lens system. The image sensor 690 is disposed on ornear the image surface 680 of the lens system.

The detailed optical data of the 6th embodiment are shown in Table 11and the aspheric surface data are shown in Table 12 below.

TABLE 11 6th Embodiment f = 1.27 mm, Fno = 2.61, HFOV = 64.0 deg. FocalSurface # Curvature Radius Thickness Material Index Abbe # Length 0Object Plano Infinity 1 Lens 1 −3.096 (ASP) 0.243 plastic 1.514 56.8−3.61 2 4.757 (ASP) 0.703 3 Ape. Stop Plano 0.001 4 Lens 2 2.733 (ASP)0.251 Plastic 1.639 23.5 −11.30 5 1.912 (ASP) 0.080 6 Lens 3 11.981(ASP) 0.482 Plastic 1.544 55.9 1.87 7 −1.093 (ASP) 0.035 8 Lens 4 1.789(ASP) 0.610 Plastic 1.544 55.9 1.31 9 −1.039 (ASP) 0.214 10 Lens 5−0.323 (ASP) 0.251 Plastic 1.639 23.5 −0.92 11 −0.929 (ASP) 0.377 12Lens 6 0.712 (ASP) 0.304 Plastic 1.544 55.9 1.51 13 4.484 (ASP) 0.350 14IR-cut filter Plano 0.300 Glass 1.517 64.2 — 15 Plano 0.133 16 ImagePlano — Note: Reference wavelength is 587.6 nm (d-line).

TABLE 12 Aspheric Coefficients Surface # 1 2 4 5 6 7 k = −1.0000E+00−1.1526E+00 −3.0646E+00 −4.5893E+01 −1.0000E+00 −8.0257E−01 A4 =4.6865E−01 6.1028E−01 −6.7556E−01 −1.3024E−02 −1.9315E−01 −7.3780E−01 A6= −8.7283E−01 −1.6009E+00 −9.4885E−01 −2.1641E+00 3.0471E−01 3.2845E+00A8 = 9.9566E−01 2.3910E+00 1.1943E+01 1.2806E+01 6.8472E+00 −1.0731E+01A10 = −6.3322E−01 −1.1434E+00 −8.7196E+01 −3.4392E+01 −2.0699E+011.7886E+01 A12 = 2.1027E−01 — — 1.0134E+01 1.6489E+01 −9.0259E+00 A14 =−2.8561E−02 — — — — — Surface # 8 9 10 11 12 13 k = −3.0728E+01−9.4703E−01 −2.2540E+00 −1.8904E+00 −1.7373E+01 −3.2389E+00 A4 =2.2829E−01 9.9629E−01 1.2316E+00 8.6212E−01 1.9364E+00 6.3275E−01 A6 =−4.9112E−01 −2.7344E+00 −2.7662E+00 −5.0033E−01 −1.0311E+01 −3.1041E+00A8 = −7.3597E−02 3.6892E+00 3.8483E+00 5.2698E−02 2.6273E+01 7.5352E+00A10 = −5.9574E−02 −2.7094E+00 −3.0899E+00 4.4307E−02 −3.8289E+01−9.9537E+00 A12 = — 7.8760E−01 1.5342E+00 −7.8459E−02 3.1810E+017.1465E+00 A14 = — — −5.7891E−01 3.1326E−02 −1.4070E+01 −2.6476E+00 A16= — — — — 2.5677E+00 3.9638E−01

In the 6th embodiment, the equation of the aspheric surface profiles ofthe aforementioned lens elements is the same as the equation of the 1stembodiment. Also, the definitions of these parameters shown in thefollowing table are the same as those stated in the 1st embodiment withcorresponding values for the 6th embodiment, so an explanation in thisregard will not be provided again.

Moreover, these parameters can be calculated from Table 11 and Table 12as the following values and satisfy the following conditions:

6th Embodiment f [mm] 1.27 TL/ImgH 2.39 Fno 2.61 TL/sin(1.6 * HFOV) [mm]4.44 HFOV [deg.] 64.0 f/R3 0.46 tan(HFOV) 2.05 f/RL 0.28 Nmax 1.639|f1/f2| 0.32 V2 + V5 47.0 f3/f4 1.43 SD/TD 0.73 (f/f3) + (f/f4) 1.65T12/T45 3.29 |SD11/SD62| 0.88 TL [mm] 4.33 f/EPD 2.61

7th Embodiment

FIG. 13 is a schematic view of an image capturing unit according to the7th embodiment of the present disclosure. FIG. 14 shows, in order fromleft to right, spherical aberration curves, astigmatic field curves anda distortion curve of the image capturing unit according to the 7thembodiment. In FIG. 13, the image capturing unit includes the lenssystem (its reference numeral is omitted) of the present disclosure andan image sensor 790. The lens system includes, in order from an objectside to an image side, a first lens element 710, a second lens element720, a third lens element 730, an aperture stop 700, a fourth lenselement 740, a fifth lens element 750, a sixth lens element 760, anIR-cut filter 770, a cover glass 775 and an image surface 780, whereinthe lens system has a total of six non-cemented lens elements (710-760)with refractive power. There is an air gap in a paraxial region betweenevery two of the first lens element 710, the second lens element 720,the third lens element 730, the fourth lens element 740, the fifth lenselement 750 and the sixth lens element 760 that are adjacent to eachother. In this embodiment, the first lens element 710 is an object-sidelens element being the closest lens element to an imaged object amongall lens elements with refractive power, and the sixth lens element 760is an image-side lens element being the closest lens element to theimage surface 780 among all lens elements with refractive power.

The first lens element 710 with negative refractive power has anobject-side surface 711 being convex in a paraxial region thereof and animage-side surface 712 being concave in a paraxial region thereof. Thefirst lens element 710 is made of plastic material and has theobject-side surface 711 and the image-side surface 712 being bothaspheric.

The second lens element 720 with positive refractive power has anobject-side surface 721 being convex in a paraxial region thereof and animage-side surface 722 being convex in a paraxial region thereof. Thesecond lens element 720 is made of plastic material and has theobject-side surface 721 and the image-side surface 722 being bothaspheric.

The third lens element 730 with positive refractive power has anobject-side surface 731 being convex in a paraxial region thereof and animage-side surface 732 being convex in a paraxial region thereof. Thethird lens element 730 is made of plastic material and has theobject-side surface 731 and the image-side surface 732 being bothaspheric.

The fourth lens element 740 with positive refractive power has anobject-side surface 741 being concave in a paraxial region thereof andan image-side surface 742 being convex in a paraxial region thereof. Thefourth lens element 740 is made of plastic material and has theobject-side surface 741 and the image-side surface 742 being bothaspheric.

The fifth lens element 750 with negative refractive power has anobject-side surface 751 being concave in a paraxial region thereof andan image-side surface 752 being convex in a paraxial region thereof. Thefifth lens element 750 is made of plastic material and has theobject-side surface 751 and the image-side surface 752 being bothaspheric. The image-side surface 752 of the fifth lens element 750 hasat least one concave shape in an off-axis region thereof.

The sixth lens element 760 with positive refractive power has anobject-side surface 761 being convex in a paraxial region thereof and animage-side surface 762 being concave in a paraxial region thereof. Thesixth lens element 760 is made of plastic material and has theobject-side surface 761 and the image-side surface 762 being bothaspheric. The image-side surface 762 of the sixth lens element 760 hasat least one convex shape in an off-axis region thereof. The image-sidesurface 762 of the sixth lens element 760 has at least one inflectionpoint in an off-axis region thereof.

The IR-cut filter 770 and the cover glass 775 are both made of glass andlocated between the sixth lens element 760 and the image surface 780,and will not affect the focal length of the lens system. The imagesensor 790 is disposed on or near the image surface 780 of the lenssystem.

The detailed optical data of the 7th embodiment are shown in Table 13and the aspheric surface data are shown in Table 14 below.

TABLE 13 7th Embodiment f = 1.12 mm, Fno = 2.85, HFOV = 70.8 deg. FocalSurface # Curvature Radius Thickness Material Index Abbe # Length 0Object Plano Infinity 1 Lens 1 5.615 (ASP) 0.800 Plastic 1.544 55.9−1.87 2 0.817 (ASP) 1.701 3 Lens 2 6.513 (ASP) 0.976 Plastic 1.639 23.53.86 4 −3.732 (ASP) 0.181 5 Lens 3 4.885 (ASP) 0.414 Plastic 1.544 55.96.08 6 −9.930 (ASP) 0.064 7 Ape. Stop Plano 0.091 8 Lens 4 −910.210(ASP) 0.692 Plastic 1.544 55.9 1.27 9 −0.693 (ASP) 0.050 10 Lens 5−0.731 (ASP) 0.300 Plastic 1.639 23.5 −1.29 11 −7.259 (ASP) 0.200 12Lens 6 1.610 (ASP) 0.688 Plastic 1.544 55.9 3.28 13 14.124 (ASP) 0.20014 IR-cut filter Plano 0.300 Glass 1.517 64.2 — 15 Plano 0.100 16 Coverglass Plano 0.400 Glass 1.517 64.2 — 17 Plano 0.568 18 Image Plano —Note: Reference wavelength is 587.6 nm (d-line).

TABLE 14 Aspheric Coefficients Surface # 1 2 3 4 5 6 k = −1.2497E+01−1.5308E+00 −9.9000E+01 −4.6436E+01 2.3840E+00 −9.9000E+01 A4 =−1.5743E−03 1.1653E−01 −3.7305E−03 −3.4455E−03 1.1228E−01 7.1245E−03 A6= 7.0097E−05 −2.3029E−02 −8.2538E−03 3.1833E−03 −2.2848E−01 −2.7917E−01A8 = — 1.0164E−03 5.5964E−03 −5.2244E−03 1.2155E−01 5.5012E−01 A10 = — —−1.6835E−03 — — — Surface # 8 9 10 11 12 13 k = −4.8378E+01 −1.4886E+00−5.8094E+00 −1.0000E+00 −1.7344E+00 −9.9000E+01 A4 = −9.5593E−023.0420E−01 −9.2912E−01 −9.4608E−02 −3.1240E−01 9.3959E−02 A6 =5.3875E−01 −4.2475E+00 2.5855E+00 −1.4802E−01 3.4287E−01 −2.0282E−01 A8= −5.4335E+00 1.0014E+01 −2.3637E+01 1.8340E+00 −3.3751E−01 1.8442E−01A10 = 3.3719E+00 −1.1406E+01 1.2839E+02 −4.2559E+00 2.5140E−01−1.0971E−01 A12 = — — −3.8805E+02 5.0183E+00 −1.1648E−01 4.1245E−02 A14= — — 6.1104E+02 −3.0487E+00 2.8936E−02 −8.6241E−03 A16 = — —−3.9454E+02 7.3584E−01 −2.9648E−03 7.3432E−04

In the 7th embodiment, the equation of the aspheric surface profiles ofthe aforementioned lens elements is the same as the equation of the 1stembodiment. Also, the definitions of these parameters shown in thefollowing table are the same as those stated in the 1st embodiment withcorresponding values for the 7th embodiment, so an explanation in thisregard will not be provided again.

Moreover, these parameters can be calculated from Table 13 and Table 14as the following values and satisfy the following conditions:

7th Embodiment f [mm] 1.12 TL/ImgH 3.41 Fno 2.85 TL/sin(1.6 * HFOV) [mm]8.41 HFOV [deg.] 70.8 f/R3 0.17 tan(HFOV) 2.87 f/RL 0.08 Nmax 1.639|f1/f2| 0.48 V2 + V5 47.0 f3/f4 4.79 SD/TD 0.33 (f/f3) + (f/f4) 1.07T12/T45 34.02 |SD11/SD62| 2.11 TL [mm] 7.72 f/EPD 2.85

The foregoing image capturing unit is able to be installed in, but notlimited to, an electronic device, including smart phones, tabletpersonal computers and wearable apparatuses. According to the presentdisclosure, the lens system has a total of six lens elements withrefractive power. The first lens element has negative refractive, thesecond lens element has refractive power, the third lens element and thefourth lens element each have positive refractive power, the fifth lenselement has negative refractive power, and the sixth lens element hasrefractive power. Therefore, the arrangement of the refractive powers isfavorable for satisfying the requirements of large field of view andcompact size simultaneously. When specific conditions are satisfied, itis favorable for assembling the lens element having stronger refractivepower to a proper position so as to prevent the manufacturing toleranceof the lens element from influencing the manufacturing yield rate.Furthermore, it is favorable for preventing the refractive power of thesecond lens element from becoming too large. Moreover, it is favorablefor reducing the incident angle of the light so as to avoid excessiveaberration. According to the present disclosure, the lens system isapplicable to the electronic device including at least three imagecapturing units so that the electronic device is for obtaining thecomposite image from the images captured by the image capturing units bypost-processing (such as digital zoom post processing, depth of focuspost processing or 3D image post processing) with the composite imagehaving high resolution and good image quality.

The foregoing description, for the purpose of explanation, has beendescribed with reference to specific embodiments. It is to be noted thatTABLES 1-14 show different data of the different embodiments; however,the data of the different embodiments are obtained from experiments. Theembodiments were chosen and described in order to best explain theprinciples of the disclosure and its practical applications, to therebyenable others skilled in the art to best utilize the disclosure andvarious embodiments with various modifications as are suited to theparticular use contemplated. The embodiments depicted above and theappended drawings are exemplary and are not intended to be exhaustive orto limit the scope of the present disclosure to the precise formsdisclosed. Many modifications and variations are possible in view of theabove teachings.

What is claimed is:
 1. A lens system comprising six lens elements, thesix lens elements being, in order from an object side to an image side:a first lens element having negative refractive power; a second lenselement; a third lens element having positive refractive power; a fourthlens element; a fifth lens element with negative refractive power havingan object-side surface being concave in a paraxial region thereof and animage-side surface being convex in a paraxial region thereof; and asixth lens element, wherein an image-side surface of the sixth lenselement has at least one inflection point in an off-axis region thereof;wherein half of a maximal field of view of the lens system is HFOV, anaxial distance between an object-side surface of the first lens elementand an image surface is TL, a maximum effective radius of theobject-side surface of the first lens element is SD11, a maximumeffective radius of the image-side surface of the sixth lens element isSD62, a maximum image height of the lens system is ImgH, and thefollowing conditions are satisfied:TL/sin(HFOV*1.6)<7.0 mm;1.30<tan(HFOV);|SD11/SD62|<2.40; andTL/ImgH<2.50.
 2. The lens system of claim 1, wherein the fourth lenselement has positive refractive power, the sixth lens element has anobject-side surface being convex in a paraxial region thereof, and theimage-side surface of the sixth lens element is concave in a paraxialregion thereof; wherein object-side surfaces and image-side surfaces ofthe first lens element, the second lens element, the third lens element,and the fourth lens element are aspheric; the six lens elements of thelens system are made of plastic material.
 3. The lens system of claim 1,wherein the axial distance between the object-side surface of the firstlens element and the image surface is TL, and the following condition issatisfied:TL<5.0 [mm].
 4. The lens system of claim 1, wherein the maximumeffective radius of the object-side surface of the first lens element isSD11, the maximum effective radius of the image-side surface of thesixth lens element is SD62, and the following condition is satisfied:|SD11/SD62|<1.25.
 5. The lens system of claim 1, wherein a maximumrefractive index among the six lens elements of the lens system is Nmax,and the following condition is satisfied:1.60<Nmax<1.70.
 6. The lens system of claim 1, wherein a focal length ofthe lens system is f, an entrance pupil diameter of the lens system isEPD, and the following condition is satisfied:f/EPD<2.65.
 7. The lens system of claim 1, wherein the fourth lenselement has an image-side surface being convex in a paraxial regionthereof.
 8. A lens system comprising six lens elements, the six lenselements being, in order from an object side to an image side: a firstlens element having negative refractive power; a second lens element; athird lens element having positive refractive power; a fourth lenselement having positive refractive power; a fifth lens element having animage-side surface being convex in a paraxial region thereof; and asixth lens element, wherein an image-side surface of the sixth lenselement has at least one inflection point in an off-axis region thereof;wherein half of a maximal field of view of the lens system is HFOV, anaxial distance between an object-side surface of the first lens elementand an image surface is TL, a maximum effective radius of theobject-side surface of the first lens element is SD11, a maximumeffective radius of the image-side surface of the sixth lens element isSD62, a maximum image height of the lens system is ImgH, and thefollowing conditions are satisfied:TL/sin(HFOV*1.6)<7.0 mm;1.30<tan(HFOV);|SD11/SD62|<2.40; andTL/ImgH<2.50.
 9. The lens system of claim 8, wherein the image-sidesurface of the sixth lens element is concave in a paraxial regionthereof, object-side surfaces and image-side surfaces of the first lenselement, the second lens element, the third lens element, and the fourthlens element are aspheric; the six lens elements of the lens system aremade of plastic material.
 10. The lens system of claim 8, wherein theaxial distance between the object-side surface of the first lens elementand the image surface is TL, and the following condition is satisfied:TL<5.0 [mm].
 11. The lens system of claim 8, wherein the maximumeffective radius of the object-side surface of the first lens element isSD11, the maximum effective radius of the image-side surface of thesixth lens element is SD62, and the following condition is satisfied:|SD11/SD62|<1.25.
 12. The lens system of claim 8, wherein a maximumrefractive index among the six lens elements of the lens system is Nmax,and the following condition is satisfied:1.60<Nmax<1.70.
 13. The lens system of claim 8, wherein a focal lengthof the lens system is f, an entrance pupil diameter of the lens systemis EPD, and the following condition is satisfied:f/EPD<2.65.
 14. The lens system of claim 8, wherein the fourth lenselement has an image-side surface being convex in a paraxial regionthereof.
 15. An electronic device, comprising at least three imagecapturing units, three of the at least three image capturing unitsbeing: a first image capturing unit comprising a first lens system and afirst image sensor, the first image sensor disposed on an image surfaceof the first lens system; a second image capturing unit comprising asecond lens system and a second image sensor, the second image sensordisposed on an image surface of the second lens system; and a thirdimage capturing unit comprising a third lens system and a third imagesensor, the third image sensor disposed on an image surface of the thirdlens system; wherein the first lens system, the second lens system andthe third lens system have different fields of view from one another,the first lens system, the second lens system and the third lens systemare all single focus lens systems, and the first image capturing unit,the second image capturing unit, and the third image capturing unit facethe same direction; wherein the first lens system comprises anobject-side lens element being closest to an imaged object among alllens elements of the first lens system; half of a maximal field of viewof the first lens system is HFOV, an axial distance between anobject-side surface of the object-side lens element and the imagesurface of the first lens system is TL, a maximum image height of thefirst lens system is ImgH, and the following conditions are satisfied:TL/sin(HFOV*1.6)<10.0 [mm];0.70<tan(HFOV); andTL/ImgH<3.0.
 16. The electronic device of claim 15, wherein theelectronic device performs zooming function by using images captured bythe first image capturing unit, the second image capturing unit and thethird image capturing unit.
 17. The electronic device of claim 16,wherein the first lens system, the second lens system and the third lenssystem are the only three lens systems facing the same direction towardthe imaged object.
 18. The electronic device of claim 15, wherein thefirst lens system comprises six lens elements.
 19. The electronic deviceof claim 18, wherein the six lens elements, in order from an object sideto an image side, are: the object-side lens element; a second lenselement; a third lens element having positive refractive power; a fourthlens element having positive refractive power; a fifth lens elementhaving negative refractive power, and; an image-side lens element;wherein there is an air gap in a paraxial region between each adjacentlens element of the six lens elements of the first lens system.
 20. Theelectronic device of claim 18, wherein the first lens system furthercomprises an image-side lens element being closest to the image surfaceamong all lens elements of the first lens system, the image-side lenselement has an image-side surface being concave in a paraxial regionthereof, and the image-side surface of the image-side lens element hasat least one convex shape in an off-axis region thereof object-sidesurfaces and image-side surfaces of the six lens elements of the firstlens system are aspheric, and the six lens elements of the first lenssystem are made of plastic material.
 21. The electronic device of claim20, wherein the second lens element has an object-side surface beingconvex in a paraxial region thereof and an image-side surface beingconcave in a paraxial region thereof.
 22. The electronic device of claim20, wherein the object-side lens element has an image-side surface beingconcave in a paraxial region thereof.
 23. The electronic device of claim20, wherein a focal length of the first lens system is f, a curvatureradius of the image-side surface of the image-side lens element is RL,and the following condition is satisfied:0.4<f/RL<3.0.
 24. The electronic device of claim 18, wherein the firstlens system further comprises an image-side lens element being closestto the image surface among all lens elements of the first lens system, amaximum effective radius of the object-side surface of the object-sidelens element is SDfs, a maximum effective radius of an image-sidesurface of the image-side lens element is SDIs, and the followingcondition is satisfied:|SDfs/SDIs|<1.25.
 25. The electronic device of claim 18, wherein amaximum refractive index among the six lens elements of the first lenssystem is Nmax, a focal length of the first lens system is f, anentrance pupil diameter of the first lens system is EPD, and thefollowing conditions are satisfied:1.60<Nmax<1.70; andf/EPD<2.65.
 26. The electronic device of claim 18, wherein half of themaximal field of view of the first lens system is HFOV, the axialdistance between the object-side surface of the object-side lens elementand the image surface of the first lens system is TL, and the followingconditions are satisfied:1.30<tan(HFOV); andTL/sin(HFOV*1.6)<7.0 [mm].
 27. The electronic device of claim 15,wherein a focal length of the first lens system is f, an entrance pupildiameter of the first lens system is EPD, and the following condition issatisfied:f/EPD<2.45.
 28. The electronic device of claim 27, wherein the focallength of the first lens system is f, the entrance pupil diameter of thefirst lens system is EPD, and the following condition is satisfied:f/EPD<2.29.
 29. The electronic device of claim 15, wherein the axialdistance between the object-side surface of the object-side lens elementand the image surface of the first lens system is TL, and the followingcondition is satisfied:TL<5.0 [mm].
 30. The electronic device of claim 15, wherein the firstlens system further comprises an aperture stop and an image-side lenselement, the image-side lens element is closest to the image surface ofthe first lens system among all lens elements of the first lens system,an axial distance between the aperture stop and an image-side surface ofthe image-side lens element is SD, an axial distance between theobject-side surface of the object-side lens element and the image-sidesurface of the image-side lens element is TD, and the followingcondition is satisfied:0.65<SD/TD<0.90.